JPS62209284A - Diaphragm type pilot operated on-off valve with pressure limiting mechanism - Google Patents

Abstract

PURPOSE:To exert pilot pressure and atmospheric pressure alternately on a diaphragm without fail, by controlling a stroke of a valve member and on-off operations of an atmospheric pressure intake valve and a pilot pressure intake valve by means of load port pressure. CONSTITUTION:When pressure in a discharge pressure intake passage 68 is exerted on a diaphragm 103, diaphragms 103 and 104 and a valve member 115 go down as one body. If so, a valve seat 120s sticks fast to a ball 120b, closing an atmospheric pressure intake valve 120, and this ball 120b presses a ball 121b via an interlocking rod 122, opening a pilot pressure intake valve 121. When pressure in a load port sufficiently drops, the ball 121b is seated in a valve seat 121s by dint of a compression spring 121c, cutting off the intake of pilot pressure into a pilot pressure passage 42.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a pilot-operated on-off valve that directly opens and closes a flow path using pilot pressure applied to a diaphragm, and particularly to an on-off valve that is equipped with a pressure limiting mechanism that adjusts its discharge pressure. to darken.

"Prior Art and its Problems" The basic structure of a pilot-operated on-off valve with this type of pressure limiting mechanism is proposed in US Pat. No. 4,540,020. This US patent directly proposes a directional valve that switches the flow path, but a directional valve is established by closing one valve and opening the other. This is a combination of on-off valves.

Figures 3 to 5 show one on-off valve and its pressure limiting mechanism among the directional control valves disclosed in this U.S. patent. First, based on these figures, we will explain the operating principle of this on-off valve. explain.

This on-off valve has a flow path block 20 and a control block 40 separated by a diaphragm 11 that also serves as a gasket, and an on-off valve section 21 is provided in this flow path block 2o. The flow path pro-ν 2o has a supply port 2 that receives pressure fluid (pressurized air) from a pressure fluid source (compressor) P.
2 and a discharge port 23 are opened, and this load port 23 penetrates to the control block 40 side. An annular passage 24 that passes through the supply port 22 and is open to the control block 40 side is located on the outer periphery of the end of the load port 23 on the control block 40 side.

The end of the load port 23 on the control block 40 side is cut down to be slightly apart from the flat diaphragm 11, and its peripheral edge constitutes a valve seat 23s that approaches and separates from the diaphragm 11. 12 is a grid (mesh body) that prevents the diaphragm 11 from being deformed into the load port 23 and the annular passage 24 due to the pressure difference between the front and back sides of the diaphragm 11;
It is.

A pilot pressure introduction valve 28 is bored in the center of the supply port 22 of the flow path block 20 so as to face directly in the flow direction of the pressure fluid from the pressure fluid source P. Small hole in diaphragm 11, control block 4
It communicates with the control chamber 52 of the pilot switching valve 5o via the pilot pressure introduction valve 41 on the 0 side and the pilot pressure introduction valve 51 branched from this introduction path, and also communicates with the control chamber 52 of the pilot switching valve 5o.
It communicates with a control chamber 62 of the pressure limiting mechanism 60 via a pilot pressure introduction valve 61 branched from 1. The pressure exerted on the pilot pressure inlet valve 28 is slightly higher than the pressure of the pressure fluid at the supply port 22 due to the laws of fluid dynamics. In this example, this pressure is used as a pilot pressure.

A pilot pressure passage 42 is bored in the control block 4o in correspondence with the center position of the load port 23, and this pilot pressure passage 42 communicates with a control chamber 62 of the pressure limiting mechanism 60. The control chamber 62 also includes a pressure reversal path 63 vertically facing the pilot pressure introduction path 61.
is opened, and this pressure reversal path 63 is connected to the pilot switching valve 50.
It passes through the control room 52.

Further, an atmospheric air inlet passage 53 opens into the control chamber 52 and is vertically opposed to the pilot pressure inlet valve 57 .

The pilot switching valve 50 is for setting the inside of the control chamber 52 to pilot pressure or atmospheric pressure, and the protruding parts of the pilot pressure introduction valve 51 and the atmospheric air introduction path 53 into the control room 52 are as follows.
The valve seats 51s and 53s are the valve seats 51s and 53s.
3s is a valve body 51v provided on the front and back of one end of the valve arm 54,
It is selectively opened and closed by 53v. In other words, the arm 54 is swingable around its middle portion, has the valve bodies 51v, 53v7 at one end, and is connected at the other end to a plunger 56 which is moved up and down by a solenoid 55. This plunger 56 is positioned at the protruding end by the force of the compression spring 57 when the solenoid 55 is demagnetized, and at this time the valve body 51v is seated on the valve seat 51s, and the valve body 51v is seated on the valve seat 51s.
V or leaves the valve seat 53s. On the other hand, when the solenoid 55 is energized, the plunger 56 is pulled, and the valve body 53v
The valve seat 53s is closed, and the valve body 51v or valve seat 513 is opened.

Note that the end of the pilot pressure passage 42 on the flow passage block 2o side is a smooth circular arc surface 42a that extends to the annular passage 24.

The pressure limiting mechanism 60 has a structure similar to the pilot switching valve 50, and the protruding portions of the pilot pressure introduction valve 61 and the pressure reversal path 63 into the control chamber 62 are connected to the valve seat 61s,
63s, and the valve seats 61s and 63s are selectively opened and closed by valve bodies 61v and 63v provided on the front and back sides of one end of the valve arm 64. In other words, the valve arm 64 is swingable around its middle portion, and has the valve bodies 61v, 63v on the front and back sides of one end thereof.

This pressure limiting mechanism 60 differs from the pilot switching valve 50 in the driving force of a valve arm 64. The other end of the valve arm 64 is connected to a plunger 65 that contacts the diaphragm 11 and moves up and down in response to the movement of the diaphragm 11. It is sandwiched between adjustment springs 66. A pressure detection chamber 67 is provided in the flow path block 20 directly below the plunger 65 across the diaphragm 1 ], and this pressure detection chamber 67 communicates with the load port 23 through a discharge pressure introduction path 68 . The spring force of the pressure adjustment spring 66 is controlled by an adjustment screw 69 screwed into the control block 40.
It can be adjusted by

According to the on-off valve equipped with the above pressure limiting mechanism, the opening and closing between the supply port 22 and the load port 23, and the opening and closing between the supply port 22 and the load port 23 are possible.
The pressure taken out from 3 can be adjusted (depressurized). In other words, when the solenoid 55 is demagnetized,
As shown in FIG. 3, since the valve body 51v is seated on the valve seat 51s and the valve body 53v is seated M from the valve seat 53s, the control chamber 5
Atmospheric pressure is introduced to the large 2 through the large 2 introduction path 53.

Therefore, the pilot pressure passage 42 also becomes atmospheric pressure via the pressure reversal passage 63 and the control chamber 62. Therefore, since the back surface of the diaphragm 11 is at atmospheric pressure, the diaphragm 11 deforms along the arc surface 42a as shown in the figure due to the discharge pressure of the pressure fluid source P, opening a passage between the supply port 22 and the load port 23, and reducing the pressure. Fluid flows into the load port 23.

On the other hand, when the solenoid 55 is energized, the valve body 53v seats on the valve seat 53s and the valve body 51v leaves the valve seat 51s, as shown in FIG. Via the valves 28, 41 and 51 the bypass pressure is introduced. For this reason, pilot pressure is led to the pilot pressure passage 42 via the pressure reversal passage 63 and the control chamber 621Fr, and the diaphragm 11 receives this pilot pressure and deforms toward the flow passage block 20 side, and the valve seat 23
s to close the flow path between the supply port 22 and the load port 23.

When the valve is opened in FIG. 3, if the pressure on the load port 23 side exceeds a certain value, the pressure on the load port 23 is guided to the pressure detection chamber 67 via the discharge pressure introduction path 68, so the diaphragm 11 deforms toward the control block 40 side and pushes up the plunger 651Fr. Then, the valve arm 64 swings so that the valve body 63v% is seated on the valve seat 63s, and at the same time, the valve body 61v is unseated from the valve seat 61s. As a result, pilot pressure is introduced into the control chamber 62 via the pilot pressure introduction valves 4 and 61, so that the diaphragm 11 seats on the valve seat 23s and directs the flow path, similar to the state shown in FIG. It will be closed. As a result of closing the flow path, when the pressure on the load port 23 side decreases, the pressure detection chamber 6
The pressure inside 7 also decreases, and the diaphragm 11 returns to its original position, returning to the state shown in FIG. That is, the flow path between the supply port 22 and the load port 23 is opened.

As a result of the above-described operations being performed in response to pressure fluctuations within the pressure detection chamber 67, the discharge pressure of the pressure fluid source P can be limited and taken out from the load port 23. The discharge pressure can be adjusted by adjusting the threading position M of the adjusting screw 69.
This can be adjusted by adjusting the force of the compression spring 66 acting on the .

The on-off valve that follows the above operating principle has no sliding parts,
Therefore, it has excellent features such as not requiring lubrication, being able to flow a large flow rate, not requiring precision machining and having good workability, and being able to be miniaturized by incorporating a pressure limiting mechanism. However, the pressure limiting characteristics of the pilot pressure passage 4
2, the pilot pressure introduction valve 61 and the pressure reversal path 63
However, it has been difficult to obtain operating characteristics that meet the requirements of the pressure limiting mechanism 60, even though it depends on how the pressure is applied.

``Object of the Invention'' The present invention solves this problem and ensures that pilot pressure and atmospheric pressure are alternately applied to the diaphragm in response to fluctuations in discharge pressure and the required pressure limit vJa when the flow path is open. The purpose is to obtain a pressure limiting mechanism that can be applied to

"Summary of the Invention" The pressure limiting mechanism of the present invention includes: a control chamber that communicates with a pilot pressure passage; a pilot pressure chamber that communicates with a pilot pressure introduction valve; an atmospheric pressure chamber that communicates with an atmospheric pressure passage; and a control room. A pilot pressure introduction valve that opens and closes between the pilot pressure chambers; A valve member that strokes when the pressure of the load port exceeds a certain value; A control chamber and a large two valve member provided in this valve member.
Pressure! and an atmospheric pressure introduction valve that opens and closes between the valve member, the atmospheric pressure introduction valve, and the pilot pressure introduction valve. The pilot pressure introduction valve is opened, and conversely, when the load port pressure decreases and the valve body returns, the pilot pressure introduction valve is closed and the atmospheric pressure introduction valve is opened.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. FIGS. 1 and 2 show an embodiment of the pressure limiting mechanism according to the present invention, and the same elements as those explained in FIGS. 3 and M4 are designated by the same reference numerals. In this embodiment, the pressure limiting mechanism 100 of the present invention includes a control block 40 and a flow path block 2.
It is configured as a valve mechanism independent from the valve mechanism o. Inside the valve case 101, there are three diaphragms 102 and 103.
．． A load port 104 and an atmospheric pressure chamber 106 are defined by the diaphragm 104, and a control chamber 107 and a pilot pressure chamber 108 are formed roughly below the diaphragm 104 in the drawing. The load port chamber 105 has the discharge pressure introduction passage 68, the atmospheric pressure chamber 106 has the pressure reversal passage 63, the control chamber 107 has the pilot pressure passage 42, and the pilot pressure chamber 108 has the pilot pressure passage. The introduction valves 61 are in communication with each other. Further, the control chamber 107 and the pilot pressure chamber 108 communicate with each other via a communication passage 110.

An annular valve body 114 is fixed to the diaphragm 102. This valve body 114 is seated on the valve seat 113 by the force of the compression spring 112, and the pressure of the load port chamber 105 is not applied to the diaphragm 103 at all times. During this period, the pressure-receiving area of the pressure exerted from the discharge pressure introduction path 68 on the diaphragm 102 is limited, or once the upward movement is started, the entire surface of the load port chamber 105 is used as the pressure-receiving area to instantly move upward. Makes a snap action movement. The spring force of the compression spring 112 is adjustable by means of an adjustment spring 109.

A valve member 175 is fixed between the diaphragm 103 and the diaphragm 104. This valve member 11
5 has an axial passage 116 and a radial passage 117 that communicate the atmospheric pressure chamber 106 and the control chamber 107. A valve seat 120s constituting the atmospheric pressure introduction valve 120 is formed on the end surface of the axial passage 116 on the control chamber]07 side, together with a ball 120b. This atmospheric pressure introduction valve 120
The ball 120b is constantly urged in a direction away from the valve seat 120s by a compression spring 120c.

A pilot pressure introduction valve 121 is provided at the lower end of the other communication passage 110 to open and close the control chamber 107 and the pilot pressure chamber 108.
Or is it set up? This pilot pressure introduction valve 121 is
Ball 121b, valve seat 121s, and this ball 12
It consists of a compression spring 121c that presses the valve 1b toward the valve seat 121s, and is normally connected to the control chamber 107 and the pilot pressure! 1
Communication with 0B is being cut off.

And the pilot pressure introduction valve 121 and the atmospheric pressure introduction valve 1
20 is interlocked by an interlocking rod 122 inserted into the communication passage 110, and further interlocked with the valve member 115. That is, in the state shown in FIG. 1, the discharge pressure introduction path 68 (
This is a state before the pressure on the load port 23) side reaches a certain value, but at this time the pilot pressure introduction valve 121 is closed and the atmospheric pressure introduction valve 120 is slightly open.

Note that pilot pressure or atmospheric pressure is selectively guided to the pressure reversal path 63 in accordance with @ demagnetization of the solenoid 55 of the pilot switching valve 50 as described above, but when the pressure limiting mechanism 60 operates, Because atmospheric pressure is guided,
In the claims and the following description, it is expressed as a pressure reversal path (atmospheric pressure introduction path) 63.

In the on-off valve equipped with the main pressure limiting mechanism 60 configured as described above, the diaphragm 11 is always in the state shown in FIG. 1, the atmospheric pressure introduction valve 120 is slightly open, and the pilot pressure introduction valve 121 is in the closed state. That is, the pilot pressure passage 42 communicates with the pressure reversal passage 63 and does not communicate with the pilot pressure introduction valve 61. Here, the solenoid 5 of the pilot switching valve 50
5 is on, pilot pressure is applied to the pressure reversal path 63, so the pilot pressure path 42 becomes pilot pressure, and the diaphragm 11 seats on the valve seat 23s to close the flow path. Therefore, the pressure in the load port 23 does not increase, and the valve member 1]5 is not displaced.

On the other hand, when the solenoid 55 of the pilot switching valve 5o is turned off, atmospheric pressure is introduced into the pressure reversal path (atmospheric pressure introduction path) 63, so that the atmospheric pressure is Passage 117 and axial passage 116
, and into the pilot pressure passage 42 via the atmospheric pressure inlet valve 120%, thus opening the passage between the supply port 22 and the load port 23.

In this valve open state, when the pressure on the load port 23 side increases, that pressure is applied to the load port chamber 105 from the discharge pressure introduction path 68. However, the valve body 114 is compressed by the compression spring 1.
12 is seated on the valve seat 113, and the pressure-receiving area of the diaphragm 102 is limited.
The diaphragm 102 is not displaced until this pressure reaches a certain value. When the pressure inside the load port chamber 105 becomes large enough to displace the diaphragm 102 and the diaphragm 102 begins to rise slightly, the load port chamber 105
The pressure inside 5 is applied to the entire valve body 114, and the pressure receiving area of the diaphragm 102 increases instantaneously. Therefore, the diaphragm 102 instantly rises and maintains that state, and the pressure in the load port chamber 106 is applied to the diaphragm 103.

A discharge pressure introduction path 68 (load port 2
When the pressure of 3) is applied, the diaphragm 103.10
4 and the valve member 115 are lowered together. Then, the valve seat 120S touches the ball 120b and the atmospheric pressure introduction valve 1
20 is closed, and the ball 120b pushes the ball 121b through the interlocking rod 122 to open the pilot pressure introduction valve 121.
1Fi, open. Therefore, pilot pressure is introduced into the control chamber 107, that is, the pilot pressure passage 42, at the same time as atmospheric pressure is introduced or stopped. Therefore, the diaphragm 11 is seated on the valve seat 23s, and the supply port 22 and the load port 23 spaces are closed.

Then, as a result of closing between the supply port 22 and the load port 23, when the pressure inside the load port 23 is sufficiently reduced, the pilot pressure introduction valve 121 will cause the ball 121b to close to the compression spring 12.
The diaphragm 103F3 and the diaphragm 104 are seated on the valve seat 121s by the force of 1c and cut off the introduction of pilot pressure into the pilot pressure passage 42, and at the same time the diaphragm 103F3 and the diaphragm 104
! Move over and return to the original position. Then the compression spring 12
The atmospheric pressure introduction valve 120 is opened by the force 0c, and the pressure reversal path (atmospheric pressure introduction path) 63 is communicated with the pilot pressure passage 42 again. That is, since atmospheric pressure is introduced into the pilot pressure passage 42 again, the diaphragm 11 is separated from the valve seat 23s, and the supply port 22 and the load port 23 are communicated with each other. In addition, in this process, the compression spring 120c
, compression spring 121c and diaphragm 103.104
It is possible to apply a mixed pressure of pilot pressure and atmospheric pressure to the pilot pressure passage 42 by appropriately setting the elasticity of the pressure. be able to.

Since the above operation is performed by fluctuations in the pressure within the load port 23, the fluid pressure taken out from the load port 23 can be limited.

Although the present invention has been described above as the simplest on-off valve, various directional switching valves can be constructed by combining these on-off valves. The present invention is naturally applicable to these directional control valves.

In the above embodiment, ball valves are used as examples of the pilot pressure introduction valve 12 and the atmospheric pressure introduction valve 120. Ball valves are characterized by their simple structure, low cost, and excellent operational reliability; however, the present invention can of course be implemented using other valves as long as the interlocking relationship between these two valves can be maintained. .

"Effects of the Invention" As described above, according to the present invention, there is provided a pulp member that strokes at the edge when the pressure on the load port side reaches a certain value, an atmospheric pressure introduction valve and a pilot pressure introduction valve to the pilot pressure passage, and Due to the interlocking relationship between the introduction valve and the valve member, either pilot pressure or atmospheric pressure can be selectively introduced into the pilot pressure passage. Therefore, the pilot pressure °
and atmospheric pressure (OK, we can obtain more ideal pressure limiting characteristics.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the pressure limiting mechanism of the present invention;
Fig. 2 is a partially cross-sectional connection diagram showing the connection state of the pressure limiting mechanism and directional control valve shown in Fig. 1, and Fig. 3 is a connection diagram shown in U.S. Pat.
．． 540,020 is a longitudinal sectional view showing one on-off valve taken out from the directional control valve equipped with a pressure limiting mechanism proposed in No. 540,020, FIG. 4 is a longitudinal sectional view in an operating state different from FIG.
FIG. 5 is a sectional view taken along line V-V in FIG. 3. 11...Diaphragm, 20-...Flow path block, 2
1... Opening/closing valve part, 22-... Supply port, 23...
Load port, 23 s"・valve seat, 24... annular passage, 28.41.51.61... pilot pressure introduction valve, 4o... control block, 42... pilot pressure passage, 50... ...Pilot switching valve, 60...Pressure limiting mechanism, 62...Control room, 63...Pressure reversal path (atmospheric pressure introduction path), 100...Pressure limiting mechanism, 701...
Pulp case, 102.103.104...Diaphragm, 105...Load port chamber, 106...Atmospheric pressure chamber, 107...Control room, 108...Pilot pressure chamber, 110...Communication path , 112... compression spring, 113
... Valve seat, 114 ... Valve body, 115 ... Valve member, 116 ... Axial direction passage, 117 ... Radial direction passage,] 20 ... Atmospheric pressure introduction valve, 121 ... Pilot pressure introduction valve, 122...interlocking rod. Patent applicant: Fujikura Rubber Industries Co., Ltd. Agent: Kunio Miura; Shigeru Matsui Figure 1 Figure 2 Figure 4

Claims (2)

[Claims] (1) A diaphragm is sandwiched between a flow path block and a control block, and a supply port and a load port to be opened and closed are provided in the flow path block, and the supply port and load port are opened to the control block side. so that the two ports can be directly opened and closed by the diaphragm, and on the other hand, a pilot pressure passage is formed on the control block side for applying pilot pressure to the diaphragm from the surface opposite to the flow path block, Furthermore, when the supply port and the load port are communicated by the pilot switching valve that selectively applies pilot pressure or atmospheric pressure to this pilot pressure passage, and the pilot switching valve , a diaphragm type pilot operated on-off valve having a pressure limiting mechanism that selectively applies pilot pressure or atmospheric pressure to the pilot pressure passage, wherein the pressure limiting mechanism has a control chamber in communication with which the pilot pressure passage communicates; A pilot pressure chamber with which the introduction passage communicates; an atmospheric pressure chamber with which the atmospheric pressure passage communicates; a pilot pressure introduction valve that opens and closes between the control chamber and the pilot pressure chamber; when the pressure of the load port exceeds a certain value. a valve member that strokes; an atmospheric pressure introduction valve provided on the valve member that opens and closes between the control chamber and the atmospheric pressure chamber; and the valve member, the atmospheric pressure introduction valve, and the pilot pressure introduction valve. When the above valve member starts to stroke due to the load port pressure, the atmospheric pressure introduction valve is closed and the pilot pressure introduction valve is opened, and conversely, when the load port pressure decreases and the valve body returns, the pilot pressure introduction valve is closed. A diaphragm-type pilot-operated on-off valve equipped with a pressure limiting mechanism characterized by being interlocked to open an atmospheric pressure introduction valve. (2) In claim 1, the pilot pressure introduction valve and the atmospheric pressure introduction valve are both constituted by ball valves, and both ball valves are interlocked with each other located between the two balls in the control chamber. A diaphragm-type pilot-operated on-off valve with a pressure limiting mechanism linked by a rod.